Reactions of thiyl radicals. V. The gas phase photolysis of methyl disulfide and ethyl disulfide mixtures in the presence of ethylene

Rao, P. M.; Knight, A. R.

doi:10.1139/v68-401

Cited by 24 publications

(6 citation statements)

References 4 publications

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“…The DMDS absorption spectrum reveals that 248 and 193 nm excitation are on different absorption features.26 Previous end product studies have shown that S-S bond scission occurs at 230-280 nm. [33][34][35] Our results confirm this interpretation. However, our study does not rule out the possible existence of other minor channels.…”

Section: Discussionsupporting

confidence: 89%

Quantum Yields of H(2S) and CH3S(2E) from the Photolysis of Simple Organosulfur Compounds at 193, 222, and 248 nm

Barone¹,

Turnipseed²,

Gierczak³

et al. 1994

J. Phys. Chem.

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The primary quantum yields for the formation of H(2S), @(H), and CH3S(2E), @(CH3S), in the photodissociation of methyl mercaptan, dimethyl sulfide (DMS), and dimethyl disulfide (DMDS) at the excimer laser wavelengths of 193, 222, and 248 nm were measured. @(H) were measured using resonance fluorescence detection of H atoms. The @(H) were 0.55 f 0.04 at 193 nm, 0.98 f 0.15 at 222 nm, and 1.09 f 0.25 at 248 nm for methyl mercaptan; (0.02 at 222 nm and <0.03 at 193 nm for DMS; and <0.06 at 222 nm and <0.08 at 193 nm for DMDS. No H atom production was observed in the 248 nm photolysis of DMS and DMDS. Using a selectively deuterated methyl mercaptan sample, CH3SD, it was shown that C-H bond scission is negligible in CH3SH photolysis at 193 and 248 nm. The @(CH3S), measured by CH3S detection via pulsed laserinduced fluorescence, were 0.93 f 0.21 at 248 nm and 0.78 f 0.10 at 193 nm for DMS; 1.65 f 0.38 at 248 nm and 1.20 f 0.14 at 193 nm for DMDS; and 0.48 f 0.10 at 193 nm for methyl mercaptan. The nature of the photodissociation processes in these sulfur compounds is discussed in light of the present measurements and the results of past studies.

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Section: Discussionsupporting

confidence: 89%

Quantum Yields of H(2S) and CH3S(2E) from the Photolysis of Simple Organosulfur Compounds at 193, 222, and 248 nm

Barone¹,

Turnipseed²,

Gierczak³

et al. 1994

J. Phys. Chem.

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“…Methyl radicals react with thiirane [ll] via simultaneous hydrogen abstraction and desulfurization and with CD3SH [12] via radical displacement, CH3 + CD3SH -CD3 + CH3SH. A similar type of displacement was obsened in the CH3S + C Z H~S S C~H~ system [13].…”

Section: Introductionsupporting

confidence: 59%

Reaction of hydrogen atoms with dimethyldisulfide

Ekwenchi

Jodhan

Strausz

1980

Int J of Chemical Kinetics

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Hydrogen atoms, generated by the mercury (3P1) sensitization of Hz, were allowed to react with dimethyldisulfide in the temperature range of 25-155'C. The only retrievable product is methanethiol, formed in the primary metathetical reaction H + CH3SSCH3 k,' CH3SH t CH3S. The intermediacy of thiyl radicals was clearly demonstrated in experiments carriedout in the presence of ethylene where one of the major products detected was ethyl methyl sulfide, formed via CH3S + CzHs -C H~S C Z H~. The major fate of the CH3S radical is recombination and disproportionation, and the yield of methanethiol formed via disproportionation contributes less than 5% to the total thiol yield. The rate coefficient of step 1, from competition with the reaction H + CzH4 k' CzHs, is k l = (5.7 f 1.2) X exp[-(100 f 100)/RT] cm3/mol sec.

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“…[1][2][3][4][5][6] Hence it is of fundamental importance to understand its photochemistry through study of energetics and structures of its photoionization products, and branching ratios as a function of photon energy in various dissociation channels. Numerous experimental measurements and theoretical calculations in the literature establish a reliable thermochemical database of organosulfur molecules, radicals, and ions.…”

Section: Introductionmentioning

confidence: 99%

Dissociative photoionization of CH3SSCH3 in the region of ∼8–25 eV

Chiang¹,

Ma²,

Shr³

1999

The Journal of Chemical Physics

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The dissociative photoionization of CH 3 SSCH 3 has been investigated in the photon energy range of ϳ8-25 eV with a molecular beam/photoionization mass spectrometry/threshold photoelectron spectrometry system using synchrotron radiation as an ionization source. For dissociation above photon energy of 11.5 eV, six fragment ions of CH 3 ϩ , C 2 H 3 ϩ , SH 3 ϩ , HCS ϩ , S 2 ϩ , and CH 2 S 2 ϩ were reported for the first time. The photoionization efficiency spectra for the parent ion and for 12 observed fragment ions, CH 3 ϩ , C 2 H 3 ϩ , SH 3 ϩ , HCS ϩ , CH 2 S ϩ , CH 2 SH ϩ , CH 3 SH ϩ , CH 3 SH 2 ϩ , CH 3 SCH 2 ϩ , S 2 ϩ , CH 2 S 2 ϩ , and CH 2 S 2 H ϩ , were measured; their branching ratios as a function of photon energy were derived. Ionization energy of 8.20Ϯ0.04 eV for CH 3 SSCH 3 and the appearance energy for each fragment ion were determined from the onsets of the photoionization efficiency spectra. Based on the appearance energy and existing thermochemical data, plausible structures of the fragment ions and their neutral counterparts are proposed. Fragmentation mechanisms that involve H migration and structural rearrangement in the dissociative photoionization processes are discussed.

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Reactions of thiyl radicals. V. The gas phase photolysis of methyl disulfide and ethyl disulfide mixtures in the presence of ethylene

Cited by 24 publications

References 4 publications

Quantum Yields of H(2S) and CH3S(2E) from the Photolysis of Simple Organosulfur Compounds at 193, 222, and 248 nm

Quantum Yields of H(2S) and CH3S(2E) from the Photolysis of Simple Organosulfur Compounds at 193, 222, and 248 nm

Reaction of hydrogen atoms with dimethyldisulfide

Dissociative photoionization of CH3SSCH3 in the region of ∼8–25 eV

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